README.md

WASM Demo

A simple Rust library compiled to WebAssembly using wasm-bindgen.

What it does

Exports a single greet(name) function that returns a greeting message.

#[wasm_bindgen]
pub fn greet(name: &str) -> String {
    format!("Hello, {}!", name)
}

Building (Optional)

Prerequisites

• Rust
• wasm-pack: cargo install wasm-pack

Build

wasm-pack build --target bundler

This generates files in the pkg/ directory:

• wasm_demo.js - JavaScript bindings (modified per Cloudflare docs)
• wasm_demo_bg.wasm - Compiled WebAssembly module
• wasm_demo_bg.js - Low-level bindings
• wasm_demo.d.ts - TypeScript definitions

Cloudflare Modification

Following Cloudflare's wasm-bindgen guide, the generated wasm_demo.js was modified to add:

import * as imports from './wasm_demo_bg.js';

// switch between both syntax for node and for workerd
import wkmod from './wasm_demo_bg.wasm';
import * as nodemod from './wasm_demo_bg.wasm';
if (typeof process !== 'undefined' && process.release.name === 'node') {
	imports.__wbg_set_wasm(nodemod);
} else {
	const instance = new WebAssembly.Instance(wkmod, {
		'./wasm_demo_bg.js': imports,
	});
	imports.__wbg_set_wasm(instance.exports);
}

export * from './wasm_demo_bg.js';

This allows the WASM to work properly with bundlers like webpack.